1. Field of the Invention
The present invention relates to a technique for an optical data transmission system, more particularly to that used inside an aircraft.
2. Background Art
In recent years, in-flight entertainment (IFE) systems have been introduced into aircrafts, allowing long-time travelers to enjoy comfortable travel owing to such as a movie, audio program, game, and Internet browsing service. Content data such as video, audio, and Internet data is usually stored in a server inside the aircraft and from there the data is sent to terminals through communication cables or wireless links. A terminal is usually placed at every passenger seat and composed of such as a unit for processing received information data, small-size video monitor, earphones, and controller.
As a conventional example related to this technical field, patent literature 1 discloses an IFE system including a server/switch unit, plural video display units, and plural fiber-optic cables. The server/switch unit includes plural servers, plural passenger-seat transceivers, and a switch. The switch provides data communications between a passenger-seat transceiver and plural servers, enabling each server to communicate with each passenger-seat transceiver through the switch. Each cable has connections to the head end and to a passenger side so that a video display unit transceiver is provided to a corresponding passenger-seat transceiver through a corresponding fiber-optic cable. Patent literature 1 claims that all the above components provide an IFE system extendable in a modular construction.
According to the technique disclosed in the above conventional example, however, the switch needs a power supply, and the switch itself has a complicated structure, limiting its downsizing and weight reduction. Conventionally, a server/switch unit and a passenger-seat transceiver are connected to each other one to one, causing a huge amount of wiring and a large amount of work for wiring. Further, the large amount of wiring increases the probability of failures (e.g. a break). Hence, a flight vehicle cannot be equipped with an IFE system freely.